Convergence electrode having pole pieces and snubbers in same slots



Nov. 21, 1967 E. E. YORNS 3,354,338

CONVERGENCE ELECTRODE HAVING POLE PIECES AND SNUBBERS IN SAME SLOTS Filed Oct. 18, 1966 INVENTOR. Zhzzrzrd 19792;

BY Elm, ME, 47% Jazz United States Patent ()fi ice 3,354,338 Patented Nov. 21, 1%67 3,354,338 CONVERGENCE ELECTRODE HAVING POLE PIECES AND SNUBBERS IN SAME SLOTS Edward E. Yarns, Owensboro, Ky., assignor to Kentucky Electronics, lino, Gwensboro, Ky., a corporation of Delaware Filed Oct. 18, 1966, Ser. No. 587,519 3 Claims. (Cl. 313-77) This invention relates to electron guns for cathode ray tubes, and more particularly, it relates to the structure of convergence electrodes in color tube guns.

In color television cathode ray tubes with three electron guns the terminal gun electrode is generally a convergence electrode which separates the three beam paths and provides a set of magnetic pole pieces for each beam to produce converging influence on the beam by electromagnetic structure mounted outside the tube envelope. These convergence electrodes thereby are generally ccntered within the glass neck of the cathode ray tube by fingers or snubbers extending from the electrodes to frictionally engage the inside circumference of the tube neck with spring pressure.

conventionally, these convergence electrodes have been made from a cylindrical cup-shaped non-magnetic member which has three sets of spaced long linear slots punched through the cylindrical walls of the cupfor receiving in registration therethrough generally L-shaped magnetic pole pieces on either side of each separate beam passing through a corresponding hole in the bottom of the cup. These pole pieces are then welded into place on the outer cup surface and a snubber finger is held in position by a jig assembly in the center of the two pole pieces and is welded to the outside surface of the electrode.

This conventional construction however, has been found unsatisfactory in accordance with this invention. One of the defects is the difficulty of maintaining tolerances on the tooling for punching the linear slots through the cylindrical walls. It has been found that the punches strike the outer surface of the cylindrical cup on a non-radial path so that the cylindrical surface of the cup tends to deflect the punches or spread the punches apart if used in pairs.

Another problem in the prior art structure is the necessity to hold the small, elongated snubber finger in alignment along an axis substantially parallel to the gun axis while it is welded into place on one end to the outer surface of the electrode. This is almost impossible to position and align accurately for hand welding, and if done by machinery, requires intricate and precise miniaturized tooling.

It is therefore an object of this invention to provide an improved convergence electrode which solves the foregoing deficiencies in the prior art.

Thus, in accordance with one aspect of the invention, a cylindrical convergence electrode has punched therein and spaced over a small segment of the cylinder surface a pair of elongated slots which have at least one generally normally extending transverse slot structure component, to thereby permit a punch shaped with a significant lateral dimension away from the elongated slot in at least one position along its length. Thus, an L-shaped or U-shaped punch structure may be used to prevent the changes in tolerance caused by spreading or deflection of the punches in the construction of prior art convergence electrode slots.

In accordance with another aspect of the invention an elongated snubber finger of generally planar construction is provided with a set of generally normally extending self alignment tabs to fit into apertures in the convergence electrode. This snubber finger therefore cooperatively fits into the transverse slot components of the elongated slots to become self-aligning and self-centering.

Detailed aspects of the invention, its nature and construction together with further features and objectives are set forth in the following specification and the accompanying drawings, wherein:

FIGURE 1 is a perspective sketch of a convergence electrode structure embodying the invention;

FIGURE 2 is a plan view in section of the convergence electrode structure taken along lines 2 -2 of FIGURE 1;

FIGURE 3 is an enlarged elevation view, partly in section of a convergence electrode provided in accordance with the teachings of this invention; and

FIGURE 4 is a broken away perspective view of a typical punch configuration used in accordance with the teachings of this invention.

The convergence electrode 10 of FIGURES 1 and 2 is fashioned to show the departures from conventional construction afforded by this invention in phantom lines. Thus, the convergence electrode 16 is a cup-shape electrode as found in the terminal electrode of a three beam color television cathode ray tube. In the bottom of the non-magnetic cup structure are three apertures 11 through which the respective beams pass as they traverse axially through the cylinder between respective pairs 14, 15 of magnetic convergence poles extending through a pair of elongated parallel slots 16, 17 punched through the cylinder walls over a small segment of less than of the cylindrical cup surface to extend longitudinally generally in a path parallel to the path of the corresponding beam through the cylinder. It may be seen that the generally planar L-shaped magnetic pole pieces 14, 15 do not extend radially into the cylinder, but bracket the path of the beam through the apertures 11. Thus, an elongated blade-like planar punch placing apertures 16, 17 through the Walls of the cylinder tends to be deflected out of tolerance and worn by the action of the cylindrical surface.

Accordingly, this invention provides for the shaping of slots 16 and 17 to have at least one generally transversely extending slot structural component 2% so that the punch 21 can be shaped as shown in FIGURE 4 in L-shape or U-shape which avoids the deflection and wear problem. Other punch shapes as noted by phantom filet 22 may be utilized without departing from the spirit of this invention.

Additionally to the L-shaped magnetic poles 14, 15 welded onto convergence cylinder 10 at points 30, etc. so that they extend into the cylinder and bracket the beam path, a set of generally planar elongated snubber fingers 31 is provided by welding onto the cylinder 10 at positions 32, etc. These fingers may be curved slightly at the outer end 34 to extend into and frictionally engage the cylindrical neck of the cathode ray tube for centering the gun. Thus, it is required that these snubber finger members be carefully aligned generally parallel to the axis of the beam and properly spaced in position to prevent tilt or misalignment.

Thus, the snubber finger is modified in form by this invention to provide generally normally extending projection tabs 40, 41 which extend through the apertures 20 in the convergence cylinder for self alignment. This structure is shown in enlarged detail form in FIGURE 3 where the U-shaped slots 16, 17 provided by this invention extend inwardly between the two pole pieces 14, 15 to provide abutting terminal surfaces 43, 44 for receiving tabs 40, 41 in self-centered and self-aligned positions intermediate the two pole pieces. Such snubber elements with tabs 40, 41 could even be conveniently placed in welded to the convergence cylinder 10 by hand operation if desired.

It is therefore evident from the foregoing description that novel and improved electrode structure is provided by this invention which is advantageous in cost, manu facture, and operating performance over conventionally used techniques to constitute a patentably improved article of manufacture and component cooperatively working as an element of an electronic system. Accordingly, those novel features descriptive of the nature and scope of the invention are defined with particularity in the appended claims.

What is claimed is:

1. A dynamic convergence electrode for an electron gun of a cathode ray tube having therein at least one pair of elongated slots punched through a small segment of the cylinder walls with the elongated direction generally parallel to the electron beam path through the electrode and shaped with at least one generally normally extending transverse slot structure component, a pair of substantially L-shaped convergence pole pieces passing through the pair of elongated slots to reside on either side of the electron beam path, an elongated generally planar finger snubber member positioned on the outer surface of the electrode with two alignment tabs protruding generally normally from the plane of the finger and mating respectively in the transverse slot component of the same slot through which the pole pieces pass, thereby aligning the snubber member in place relative to the direction and placement of the slots, and means afiixing said snubber member to the convergence electrode in said aligned place.

2. An electrode as defined in claim 1 wherein the transverse slots structure extend between said two slots at one end and the alignment tabs abut the closest extremities of the two transverse slots to be centered between the two elongated portions of the slots.

3. An electrode as defined in claim 2 wherein the transverse slots structure extends along the length of the longitudinal slot structure a substantial distance parallel to the longitudinal slot to thereby provide abutting surfaces with the alignment tabs of said snubber finger that hold the snubber finger in a longitudinal direction substantially parallel with the path of the electron beam through the cylinder.

No references cited.

DAVID J. GALVIN, Primary Examiner.

ROBERT SEGAL, Examiner. 

1. A DYNAMIC CONVERGENCE ELECTRODE FOR AN ELECTRON GUN OF A CATHODE RAY TUBE HAVING THEREIN AT LEAST ONE PAIR OF ELONGATED SLOTS PUNCHED THROUGH A SMALL SEGMENT OF THE CYLINDER WALLS WITH THE ELONGATED DIRECTION GENERALLY PARALLEL TO THE ELECTRON BEAM PATH THROUGH THE ELECTRODE AND SHAPED WITH AT LEAST ONE GENERALLY NORMALLY EXTENDING TRANSVERSE SLOT STRUCTURE COMPONENT, A PAIR OF SUBSTANTIALLY L-SHAPED CONVERGENCE POLE PIECES PASSING THROUGH THE PAIR OF ELONGATED SLOTS TO RESIDE ON EITHER SIDE OF THE ELECTRON BEAM PATH, AN ELONGATED GENERALLY PLANAR FINGER SNUBBER MEMBER POSITIONED ON THE OUTER SURFACE OF THE ELECTRODE WITH TWO ALIGNEMNT TABS PROTRUDING GENERALLY NORMALLY FROM THE PLANE OF THE FINGER AND MATING RESPECTIVELY IN THE TRANSVERSE SLOT COMPONENT OF THE SAME SLOT THROUGH WHICH THE POLE PIECES PASS, THEREBY ALIGNING THE SNUBBER MEMBER IN PLACE RELATIVE TO THE DIRECTION AND PLACEMENT OF THE SLOTS, AND MEANS AFFIXING SAID SNUBBER MEMBER TO THE CONVERGENCE ELECTRODE IN SAID ALIGNED PLACE. 